CN108605345B - User terminal, radio base station, and radio communication method - Google Patents

Abstract

Communication is appropriately performed even when allocation is controlled in a frequency unit (for example, subcarrier unit) smaller than a resource allocation unit in the conventional LTE system. Comprising: a reception unit configured to receive downlink control information in a predetermined bandwidth on a downlink control channel included in a predetermined period; and a control unit configured to control uplink data transmission based on the downlink control information, wherein the control unit controls a start timing of uplink data transmission with reference to a subframe in which a downlink control channel is transmitted last in the predetermined period.

Description

User terminal, radio base station, and radio communication method

Technical Field

The present invention relates to a user terminal, a radio base station, and a radio communication method in a next-generation mobile communication system.

Background

In a UMTS (Universal Mobile telecommunications System) network, Long Term Evolution (LTE) is standardized for the purpose of higher data rate, lower latency, and the like (non-patent document 1). Further, for the purpose of further widening LTE bandwidth and increasing LTE speed, successor systems of LTE (for example, also referred to as LTE-a (LTE advanced), FRA (Future Radio Access), 4G, 5G, LTE rel.13, 14, 15 to 15, and the like) have been studied.

In recent years, with the cost reduction of communication devices, technology development of Machine-to-Machine communication (M2M: Machine-to-Machine) in which devices connected to a network automatically control without mutual human-hand communication has been actively performed. In particular, 3GPP (Third Generation Partnership Project) is performing standardization relating to optimization of MTC (Machine Type Communication), which is also a cellular system for inter-Machine Communication in M2M (non-patent document 2). MTC User terminals (MTC UEs (User Equipment)) are considered to be used in a wide range of fields such as electric meters, gas meters, vending machines, vehicles, other industrial Equipment, and the like.

Documents of the prior art

Non-patent document

Non-patent document 1: 3GPP TS 36.300 "Evolved Universal Radio Access (E-UTRA) and Evolved Universal Radio Access Network (E-UTRAN); (ii) an Overall description; stage 2 "

Non-patent document 2: 3GPP TR 36.888 "Study on Provisions of Low-cost Machine-Type Communications (MTC) User Equipment (UEs) based on LTE (Release 12)"

Disclosure of Invention

Problems to be solved by the invention

In MTC, from the viewpoint of Cost reduction and improvement of a coverage area in a cellular system, there is an increasing demand for MTC user terminals (LC (Low-Cost) -MTC terminals, LC-MTC UEs) that can be implemented by a simple hardware structure. As a communication method of such LC-MTC terminals, LTE communication in a very Narrow Band domain (for example, may also be referred to as NB-IoT (Narrow Band Internet of Things)), NB-LTE (Narrow Band LTE), NB cellular IoT (Narrow Band cellular Internet of Things), new scheme (clean tile), and the like) is being studied. In the following, it is assumed that "NB-IoT" described in the present specification includes the above-described NB-LTE, NB cellular IoT, a completely new scheme, and the like.

It is also assumed that the use band of a user terminal supporting NB-IoT (hereinafter, referred to as an NB-IoT terminal) is limited to a narrower band (e.g., 180kHz, 1 Resource Block (also referred to as Resource Block (RB), Physical Resource Block (PRB), etc.)) than the smallest system band (1.4MHz) of the existing LTE system (e.g., LTE system before rel.12)).

In this way, it is assumed that, for an NB-IoT terminal whose usage band is limited to a narrowband domain as compared with an existing user terminal (e.g., an LTE terminal before rel.12), resource allocation in a frequency unit (e.g., subcarrier unit) smaller than a PRB, which is a resource allocation unit in the LTE system, is required.

However, in the conventional LTE system, resource allocation in PRB units is assumed for user terminals, and for NB-IoT terminals, there is a problem in how to allocate resources in frequency units smaller than 1PRB and control communication.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a user terminal, a radio base station, and a radio communication method that can perform communication appropriately even when allocation is controlled in a frequency unit (for example, subcarrier unit) smaller than a resource allocation unit in a conventional LTE system.

Means for solving the problems

A user terminal according to an aspect of the present invention includes: a reception unit configured to receive downlink control information in a predetermined bandwidth on a downlink control channel included in a predetermined period; and a control unit configured to control uplink data transmission based on the downlink control information, wherein the control unit controls a start timing of uplink data transmission with reference to a subframe in which a downlink control channel is transmitted last in the predetermined period.

Effects of the invention

According to the present invention, even when allocation is controlled in a frequency unit (for example, subcarrier unit) smaller than a resource allocation unit in the conventional LTE system, communication can be appropriately performed.

Drawings

Fig. 1 is an explanatory diagram of the use band of an NB-IoT terminal.

Fig. 2A and 2B are diagrams showing an example of NB-IoT resource elements.

Fig. 3A and 3B are diagrams illustrating an example of a subframe set.

Fig. 4A and 4B are diagrams illustrating another example of a subframe set.

Fig. 5 is a diagram showing an example of UL transmission using the timing of the conventional system.

Fig. 6 is a diagram showing another example of UL transmission using the timing of the conventional system.

Fig. 7 is a diagram illustrating an example of UL transmission according to the present embodiment.

Fig. 8 is a diagram illustrating another example of UL transmission according to the present embodiment.

Fig. 9 is a diagram illustrating another example of UL transmission according to the present embodiment.

Fig. 10 is a diagram illustrating another example of UL transmission according to the present embodiment.

Fig. 11A and 11B are diagrams illustrating an example of DL transmission according to the present embodiment.

Fig. 12A and 12B are diagrams illustrating another example of DL transmission according to the present embodiment.

Fig. 13 is a schematic configuration diagram showing a radio communication system according to the present embodiment.

Fig. 14 is a diagram showing an example of the overall configuration of the radio base station according to the present embodiment.

Fig. 15 is a diagram showing an example of a functional configuration of the radio base station according to the present embodiment.

Fig. 16 is a diagram showing an example of the overall configuration of the user terminal according to the present embodiment.

Fig. 17 is a diagram showing an example of a functional configuration of the user terminal according to the present embodiment.

Fig. 18 is a diagram showing an example of hardware configurations of the radio base station and the user terminal according to the present embodiment.

Detailed Description

In the NB-IoT terminal, studies are being made to allow for a reduction in processing power while simplifying a hardware structure. For example, in an NB-IoT terminal, it is considered to apply a reduction in peak rate, a restriction on a Transport Block Size (TBS), a restriction on a Resource Block (also referred to as a RB, a Physical Resource Block (PRB), or the like), a restriction on a received RF (Radio Frequency), or the like, as compared with a conventional user terminal (for example, an LTE terminal prior to rel.12).

Unlike an LTE terminal in which the upper limit of the usage Band is set to the system Band (e.g., 20MHz (100RB), 1 component carrier, etc.), the upper limit of the usage Band of an NB-IoT terminal is limited to a prescribed Narrow Band (NB: Narrow Band, e.g., 180kHz, 1.4 MHz). For example, the predetermined narrowband region may be the same as the minimum system bandwidth (e.g., 1.4MHz, 6PRB) of the conventional LTE system (LTE system before rel.12, hereinafter also simply referred to as LTE system), or may be a partial bandwidth (e.g., 180kHz, 1 PRB).

As described above, the NB-IoT terminal may be referred to as a terminal that uses a narrower upper limit of a bandwidth than an existing LTE terminal, and that can transmit and/or receive (hereinafter, referred to as transmission and reception) in a narrower bandwidth (for example, a bandwidth narrower than 1.4MHz) than an existing LTE terminal. Research is being conducted to operate the NB-IoT terminal within the system band of the LTE system in consideration of backward compatibility with the existing LTE system. For example, in the system band of the LTE system, frequency reuse may be supported between an NB-IoT terminal whose band is restricted and an existing LTE terminal whose band is not restricted. Further, the NB-IoT may be operated not only within the LTE system band domain but also using a guard band (guard band) or a dedicated frequency between carriers adjacent to the LTE system band domain.

Fig. 1 is a diagram showing an example of the configuration of a narrowband domain using a bandwidth domain to be an NB-IoT terminal. In fig. 1, the usage band of the NB-IoT terminal is set to be a part of the system band (e.g., 20MHz) of the LTE system. In addition, after fig. 1, the use band of the NB-IoT terminal is set to 180kHz, but the present invention is not limited thereto. The use band of the NB-IoT terminal may be narrower than the system band (e.g., 20MHz) of the LTE system, and may be, for example, equal to or less than the use band (e.g., 1.4MHz) of the LC-MTC terminal of rel.13.

Further, it is preferable to have the following structure: the frequency location of the narrowband domain using the band domain, which becomes an NB-IoT terminal, may vary within the system band domain. For example, it is preferable that NB-IoT terminals use different frequency resources for each predetermined period (e.g., subframe) to perform communication. This enables traffic offload (traffic offload) or a frequency diversity effect for the NB-IoT terminal, and suppresses a decrease in frequency utilization efficiency. Therefore, it is preferable that the NB-IoT terminal has a function of performing RF re-tuning (tuning) in consideration of application of frequency hopping or frequency scheduling.

In addition, the NB-IoT terminal may use different banddomains in the downlink and uplink, and may also use the same banddomain. The Band used for Downlink transmission and reception may also be referred to as a Downlink narrowband region (DL NB: Downlink Narrow Band). The Band used for Uplink transmission and reception may also be referred to as an Uplink narrowband region (UL NB: Uplink Narrow Band).

In addition, the NB-IoT terminal receives Downlink Control Information (DCI) using a Downlink Control channel configured (allocate) in the narrowband domain. The Downlink Control Channel may be referred to as PDCCH (Physical Downlink Control Channel), EPDCCH (Enhanced Physical Downlink Control Channel), M-PDCCH (mtc PDCCH), NB-PDCCH, or the like.

In addition, the NB-IoT terminal receives downlink data using a downlink shared channel configured in the narrowband domain. The Downlink Shared Channel may be referred to as a PDSCH (Physical Downlink Shared Channel), an M-PDSCH (mtc PDSCH), an NB-PDSCH, or the like.

Furthermore, the NB-IoT terminal transmits retransmission Control Information (Hybrid Automatic retransmission reQuest-acknowledgement (HARQ-ACK)), Uplink Control Information (Uplink Control Information) such as Channel State Information (CSI), and the like, using an Uplink Control Channel configured in the narrowband domain. The Uplink Control Channel may be referred to as a PUCCH (Physical Uplink Control Channel), an M-PUCCH (mtc PUCCH), an NB-PUCCH, or the like.

In addition, the NB-IoT terminal receives UCI and/or uplink data using an uplink shared channel configured in the narrowband domain. The Uplink Shared Channel may be referred to as a PUSCH (Physical Uplink Shared Channel), an M-PUSCH (mtc PUSCH), an NB-PUSCH, or the like.

Not limited to the above channels, the conventional channel used for the same purpose may be denoted by adding "M" indicating MTC or "N" indicating NB-IoT or "NB". Hereinafter, the downlink control channel, the downlink shared channel, the uplink shared channel, and the uplink shared channel used in the narrowband region are referred to as PDCCH, PDSCH, PUCCH, and PUSCH, respectively, but as described above, the designation is not limited thereto.

In NB-IoT, the same downlink signal (e.g., PDCCH, PDSCH, etc.) and/or uplink signal (e.g., PUCCH, PUSCH, etc.) may be transmitted and received repeatedly through a plurality of subframes in order to enhance coverage. The number of subframes for transmitting and receiving the same downlink signal and/or uplink signal is also referred to as repetition number (repetition number). The number of iterations may be represented by an iteration level. This level of repetition may also be referred to as a Coverage Enhancement (CE) level.

In the NB-IoT as above, studies are being made to support transmission using a single tone (single-tone transmission) and transmission using a plurality of tones (multi-tone transmission) in uplink transmission. Here, a tone means the same as a subcarrier, and means each band divided using a band (for example, 180kHz, 1 resource block).

In single tone transmission, research is being conducted to support the same subcarrier spacing (i.e., 15kHz) as the existing LTE system and a subcarrier spacing (e.g., 3.75kHz) narrower than the LTE system. On the other hand, in multi-tone transmission, supporting the same subcarrier spacing (i.e., 15kHz) as the LTE system is being studied. In the case of a subcarrier spacing of 15kHz, 1PRB (180kHz) consists of 12 subcarriers. In addition, in the case where the subcarrier spacing is 3.75kHz, 1PRB is composed of 48 subcarriers. Needless to say, the subcarrier spacing applicable to this embodiment is not limited to this.

Further, studies are being made on NB-IoT terminals performing uplink transmission (for example, transmission of PUSCH or/and PUCCH) by the number of tones (subcarriers) notified from the radio base station. Examples of combinations of the numbers of tones include {1, 3, 6, 12 }. In this way, the number of tones selected from the predetermined combination is set (configure) by higher layer signaling (for example, RRC (Radio Resource Control) signaling or broadcast information), and the NB-IoT terminal can perform uplink transmission with the set number of tones.

Fig. 2A and 2B are diagrams showing an example of resource units in NB-IoT. In fig. 2A, description will be given of a case where {1, 3, 6, 12} is used as a combination of the number of tones (subcarriers), but the combination of the number of tones is not limited to this. For example, a combination of {1, 2, 4, 12} may also be used.

As shown in fig. 2A, the time unit of the 1-resource unit is changed according to the number of tones (i.e., the number of subcarriers and the frequency unit) constituting the 1-resource unit. Specifically, the time unit constituting the 1-resource unit is made longer in accordance with the number of tones (subcarriers) constituting the 1-resource and/or the reduction in the subcarrier interval.

For example, in fig. 2A, when the subcarrier interval is 15kHz, which is the same as that of the conventional LTE system, and the number of tones is 12, 6, 3, and 1, the time units of 1 resource element are 1ms, 2ms, 4ms, and 8ms, respectively. When the subcarrier spacing is 3.75kHz times 1/4 times that of the conventional LTE system and the number of tones is 1, the time unit of 1 resource element is 32 ms.

Fig. 2B shows an example of uplink data (e.g., PUSCH) transmission when the number of tones is 1 (tone). In NB-IoT, as shown in fig. 2B, uplink data of different user terminals can be mapped to different subcarriers in the same resource block to control transmission.

In fig. 2A and 2B, a Transport Block (TB) that is a storage unit of data may be mapped to a resource unit of 1 or a plurality of resource units. The resource elements described above can be applied to downlink transmission as well as uplink transmission.

In NB-IoT, since the communication band is severely restricted (e.g., 1RB (180kHz)), a configuration in which a plurality of consecutive subframes are set for downlink control channel (NB-PDCCH) transmission is considered. The consecutive subframes set for NB-PDCCH transmission or reception are also referred to as a Subframe set (Subframe set), a consecutive Subframe set, and a control region. The information on the subframe set can be notified from the radio base station to the user terminal using higher layer signaling (e.g., RRC signaling, broadcast information, etc.) and/or downlink control information.

The radio base station can allocate a downlink control channel to a subframe set for the NB-IoT downlink control channel and control transmission of downlink control information (UL grant and/or DL assignment). The user terminal receives a downlink control channel (downlink control information) included in the subframe set, thereby controlling reception of DL data and/or transmission of UL data scheduled by the downlink control information.

When a subframe set for a downlink control channel is set, 2 methods are considered as a method for transmitting Downlink Control Information (DCI). As a first method, a method of transmitting only 1 piece of DCI in a subframe set of DL is considered (see fig. 3A).

Fig. 3A shows a case where 1 piece of DCI is allocated to each of the first Subframe set (Subframe set #1) and the second Subframe set (Subframe set # 2). Fig. 3A shows a case where 1 piece of DCI (for example, DCI corresponding to 1 TB) is allocated to 2 subframes (1 piece of DCI is transmitted using 2 subframes). In the following description, a case where 1 piece of DCI is transmitted using 2 subframes is also shown, but the allocation method of 1 piece of DCI is not limited to this.

As in the conventional system, it is assumed that the user terminal performs tone UL data transmission in a subframe after a predetermined period (for example, after 4ms) after receiving downlink control channel (DCI). In the following description, a case where the time unit of the resource unit of the tone is 8ms is shown, but the present invention is not limited thereto.

In a conventional system (e.g., eMTC, category M1), a user terminal acquires data allocation information from DCI decoded in a subframe # n in which a downlink control channel is transmitted, and acquires data allocation information in a subframe # n + k after a predetermined period of the subframe # n₁And starting to receive downlink data. In addition, the user terminal receives the subframe # n + k of the downlink control channel after a predetermined period of the subframe # n₂Transmission of upstream data is started. Here, k is specified₁＝1、k ₂4. When the repeated transmission is applied to the downlink control channel, the user terminal controls UL transmission or DL reception with reference to a subframe in which the last downlink control channel is transmitted.

As shown in fig. 3A, when DCI is transmitted using different subframe sets, the transmission timing difference of each DCI increases. Therefore, uplink data scheduled by each DCI (e.g., PUSCH #1, PUSCH #2) is allocated in different time domains (subframes) of the same subcarrier. In this case, resources that are not used by any user terminal (unused subcarriers) are generated in the frequency direction, and there is a concern that the resource use efficiency may be reduced.

As a second method, a method of transmitting a plurality of DCIs in 1 subframe set (see fig. 3B) is considered. Fig. 3B shows a case where a plurality of (here, 2) DCIs are allocated to 1 subframe set. Fig. 3B shows a case where 1 DCI is allocated to 2 subframes and 2 DCI is allocated to consecutive subframes.

As in the conventional system, it is assumed that the user terminal performs tone UL data transmission in a subframe after a predetermined period (for example, 4ms) after receiving the downlink control channel. In this case, since the transmission timing difference of each DCI can be reduced, UL data (PUSCH #1 and PUSCH #2) scheduled by each DCI can be allocated so as to overlap in the time domain (subframe), and thus different subcarriers can be allocated by frequency division multiplexing. In this case, the number of unused subcarriers in 1PRB can be reduced compared to fig. 3A, and resource utilization efficiency can be improved to some extent.

In this way, a configuration in which a plurality of DCIs are included in a subframe set (control region) is considered from the viewpoint of frequency use efficiency (see fig. 4A). Further, a configuration may be adopted in which a plurality of pieces of DCI to which repetitive transmission (coverage enhancement) is applied are also included in the same subframe set (see fig. 4B). Fig. 4A shows a case where a plurality of DCIs (DCI #1 to #3) to which repetitive transmission is not applied are included in the same subframe set, and fig. 4B shows a case where a plurality of DCIs (DCI #1 and #2) to which repetitive transmission (repetition number 4 in this case) is applied are included in the same subframe set.

On the other hand, even when a plurality of DCIs are included in the same subframe set, if UL data and/or DL data are allocated at a timing specified in the conventional system, it is not possible to sufficiently achieve resource utilization efficiency. For example, as shown in fig. 5, a case is assumed where 6 DCIs (here, UL grants) are included in 1 subframe set. In this case, when the transmission/reception timing of the existing system is used, UL data (PUSCH #1- #6) is allocated for a predetermined period (for example, 4ms) after the sub-frame in which each DCI (DCI #1- #6) is allocated.

In this case, UL data (PUSCH #1) scheduled by the first DCI #1 having an earlier allocation timing and UL data (PUSCH #2 and #3) scheduled by the second DCI #2 and the third DCI #3 are partially allocated to overlap in the same time domain. Therefore, control is performed such that these UL data are allocated on different subcarriers. On the other hand, since the UL data scheduled by the first DCI #1 (PUSCH #1) and the UL data scheduled by the fourth DCI #4 (PUSCH #4) do not overlap in the time domain, it is considered that the allocation is controlled using the same subcarrier.

However, an unused Resource (Resource fragment) is generated between the UL data (PUSCH #1) of the first DCI #1 and the UL data (PUSCH #4) of the fourth DCI # 4. Similarly, unused resources are generated between the UL data (PUSCH #2) of the second DCI #2 and the UL data (PUSCH #5) of the fifth DCI #5, and between the UL data (PUSCH #3) of the third DCI #3 and the UL data (PUSCH #6) of the sixth DCI # 6.

Fig. 6 shows a case where 2 pieces of DCI (DCI #1 and DCI #2) that are repeatedly transmitted (repetition number 4) are provided. When the repeated transmission is applied, even if the user terminal can receive DCI in the middle of the repeated transmission (here, the number of repetitions 2), the user terminal needs to control transmission of UL data with reference to the reception timing of the last DCI (DCI transmitted at the 4th time). In this case, the allocation position of the uplink data (here, PUSCH #1, PUSCH #2) is determined in the subframe set according to the position of the DCI which is repeatedly transmitted. Therefore, depending on the position or the number of repetitions of DCI, uplink data (here, PUSCH #1 and PUSCH #2) cannot be efficiently allocated, and the resource utilization efficiency cannot be sufficiently improved.

As described above, even when a plurality of DCIs are set in a subframe set, there is a possibility that the resource utilization efficiency cannot be sufficiently achieved if the transmission/reception timing of the existing system is applied. Further, as the number of pieces of DCI allocated to a subframe set or the number of repeated transmissions of DCI increases, unused resources may be generated more, and the resource utilization efficiency may be further reduced.

Therefore, the present inventors have focused on the fact that, when a plurality of DCIs are included in the same subframe set, unused resources (resource fragments) are generated in the time direction in UL data allocation when the conventional transmission timing is used, and have conceived to control the transmission start timing of UL data scheduled by the DCIs included in the same subframe set to be the same.

For example, as an aspect of the present invention, control is performed such that uplink data transmission scheduled by DCI (UL grant) included in the same subframe set is started from a predetermined subframe. Thus, even when a plurality of DCIs are included in the same subframe set and the allocation of uplink data is controlled, it is possible to suppress the occurrence of unused resources between different uplink data (particularly, in the time direction) and improve the utilization efficiency of resources.

In addition, as another aspect of the present invention, it is possible to control downlink data reception scheduled by DCI (DL assignment) included in the same subframe set from a predetermined subframe.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following, the use bandwidth of the NB-IoT terminal is limited to 180kHz (1PRB), which is a narrower bandwidth than the minimum system bandwidth (1.4MHz) of the conventional LTE system, but the present invention is not limited thereto. The bandwidth used by the NB-IoT terminal in the present embodiment may be any bandwidth as long as it is a narrower bandwidth than the system bandwidth of the existing LTE system, such as 1.4MHz equal to the smallest system bandwidth of the existing LTE system or a narrower bandwidth than 180 kHz.

In the following, a case where the subcarrier spacing is 15kHz and the 180kHz is composed of 12 subcarriers is exemplified, but the present invention is not limited thereto. This embodiment can be suitably applied also to a case where the subcarrier interval is 3.75kHz and 180kHz is configured by 48 subcarriers, for example. As described in fig. 2A and 2B, the duration of the 1 resource element may be changed according to the subcarrier interval.

Note that, in the following description, a resource allocation unit is described as "subcarrier (tone)", but the resource allocation unit in the present embodiment is not limited thereto, and may be any frequency unit smaller than a resource allocation unit (PRB) in the conventional LTE system.

(first mode)

In the first aspect, a case of controlling the start timing of uplink data transmission scheduled by Downlink Control Information (DCI) included in a subframe set will be described. In the following description, the case of transmitting uplink data by a tone (single subcarrier) is described, but the present invention can also be applied to the case of transmitting by a multi-tone (multiple subcarriers). The plurality of DCIs included in the subframe set may be DCIs that control scheduling of different user terminals, or may be DCIs that control scheduling of one user terminal by a part or all of the DCIs.

Fig. 7 shows a case where 6 pieces of DCI (DCI #1 to #6) are set in the same subframe set, and transmission start timings (allocation start positions) of uplink data (PUSCH #1 to #6) scheduled by the 6 pieces of DCI are controlled to be the same. Specifically, UL data (PUSCH #1- #6) scheduled by DCI #1- #6 respectively is transmitted from a predetermined subframeAnd (5) feeding. The predetermined subframe may be a subframe (for example, SF # n + k) after a predetermined period from the last subframe (for example, SF # n) of the subframe set₂). Here, k can be set₂An integer greater than 0 (e.g., 4).

The radio base station includes different UL allocation information (e.g., resources (subcarriers) for UL data) in DCI (UL grant) included in the same subframe set, and transmits the DCI to the user terminal. When receiving DCI included in a subframe set, a user terminal starts UL data transmission from a predetermined subframe regardless of the subframe number of the received DCI or the like.

The user terminal can decide allocation resources (subcarriers) of UL data based on the received DCI. Further, the user terminal can determine the timing of the last subframe (SF # n) of the subframe set based on information (e.g., information on the subframe set) notified by higher layer signaling and/or DCI. In addition, the information on the timing of the last subframe of the subframe set may be the number of subframes constituting the subframe set, an offset amount for determining the position of the subframe set, and the like.

In this way, by controlling the transmission start timings of UL data scheduled by DCI included in the same subframe set to be the same, it is possible to transmit a plurality of UL data using different subcarriers in the overlapping time domain (subframe). Thus, compared to the case where the transmission start timing of UL data is determined based on the reception timing of DCI (e.g., the received subframe number) (e.g., fig. 5 and 6), it is possible to suppress the occurrence of unused resources between different UL data. This can improve the resource utilization efficiency.

The present embodiment can also be applied to a case where repeated transmission (coverage enhancement) is used. Fig. 8 shows a case where 2 pieces of DCI (DCI #1 and DCI #2) to which repeated transmission (repetition number 4) is applied are set in the same subframe set. Note that, the case where the transmission start timings of the uplink data (for example, PUSCH #1 and #2) scheduled by the 2 pieces of DCI are controlled to be the same is shown.

Specifically, transmission of UL data (PUSCH #1, #2) scheduled by DCI #1, #2, respectively, is controlled from a predetermined subframe. The predetermined subframe can be set to be the last from the subframe setA subframe (e.g., SF # n + k) after a predetermined period from the subframe (e.g., SF # n)₂). Here, k can be set₂Is a value greater than 0 (e.g., 4).

The user terminal determines an allocation resource (subcarrier) of UL data based on the received DCI, and starts UL data transmission from a predetermined subframe. Here, the case where the user terminal performs tone transmission of the inverse number 2 for UL data is shown. In this case, it is possible to suppress the occurrence of unused resources between different uplink data. The number of iterative transmissions applied to uplink data scheduled by different DCIs in the same subframe set may be the same or different.

In fig. 7 and 8, a case is shown in which a predetermined subframe to be a transmission start timing of UL data is determined with reference to the last subframe of the subframe set, but the present embodiment is not limited thereto. For example, the predetermined subframe may be determined based on a subframe in which the last DCI (downlink control channel) included in the subframe set is transmitted. As the last DCI, only DCI scheduling UL transmission (UL grant) may be considered, or both DCI scheduling UL transmission and DCI scheduling DL transmission (DL assignment) may be considered.

Fig. 9 and 10 show a case where the UL transmission start timing is determined based on the subframe in which the last DCI (DCI #6) among the DCIs (DCI #1 to #6) included in the subframe set is transmitted. Fig. 9 shows a case where the repetitive transmission is not used (a case of normal coverage), and fig. 10 shows a case where the repetitive transmission is applied (a case of enhanced coverage).

The radio base station can include information on a subframe (SF # m) in which the last DCI (DCI #6) included in the subframe set is transmitted in the DCI (e.g., DCI #1 to #6) and notify the user terminal of the information. The user terminal determines a subframe (for example, SF # m) in which DCI #6 is transmitted based on information included in the DCI, and determines a subframe (for example, SF # m + k) after a predetermined period from the subframe₂) The UL transmission is started. Here, k can be set₂A value greater than 0 (e.g., 4).

In this way, by controlling the transmission start timings of UL data scheduled by DCI included in the same subframe set to be the same, it is possible to transmit a plurality of UL data using different subcarriers in the overlapping time domain. Further, by determining the transmission start timing of UL data based on the transmission timing of the last DCI included in the subframe set, the transmission start timing of UL data can be earlier than in fig. 7 and 8. As a result, the resource utilization efficiency can be further improved, and the delay can be reduced.

The radio base station may notify the user terminal of information on a predetermined subframe which becomes a start timing of UL transmission, the information being included in the DCI. The information on the predetermined subframe may be any information for determining the predetermined subframe, and may be, for example, the number of the predetermined subframe itself or a subframe serving as a reference for determining the predetermined subframe. In this case, the radio base station can transmit information on a predetermined subframe to the user terminal, including the information on the predetermined subframe in each DCI transmitted in the same subframe set.

(second mode)

In the second aspect, a case of controlling the reception start timing of downlink data scheduled by DCI included in a subframe set will be described. In the following description, the case where downlink data is transmitted in multi-tone (a plurality of subcarriers (for example, 1PRB)) is described, but the present invention can also be applied to the case where downlink data is transmitted in single tone (single subcarrier).

Fig. 11A shows a case where 7 pieces of DCI (DCI #1 to #7) are set in a subframe set. Here, it is assumed that uplink data is scheduled by 6 pieces of DCI (DCI #1 to #6) and downlink data is scheduled by 1 piece of DCI (DCI # 7). That is, DCI #1 to #6 correspond to UL grant, and DCI #7 corresponds to DL assignment (DL assignment). The number of DCIs for downlink scheduling and the number of DCIs for uplink scheduling are not limited to these.

In this way, a configuration can be made such that only 1 DL assignment is included for 1 subframe set. In this case, the allocation control can be simplified in the case of transmitting DL data in multiple carriers. Alternatively, multiple DL assignments may be included in 1 subframe set.

The user terminal starts reception of DL data (PDSCH) scheduled by DCI #7 from a predetermined subframe. The predetermined subframe may be a subframe (for example, SF # n + k) after a predetermined period from the last subframe (for example, SF # n) of the subframe set₁). This is achieved byIn can be provided with k₁Is an integer greater than 0 (e.g., 1). The first scheme can be applied to transmission of UL data (PUSCH #1- #6) scheduled by DCI #1- #6, respectively.

The radio base station includes DL assignment information (for example, resources (subcarriers) for DL data) in DCI (DL assignment) included in a subframe set, and transmits the DCI to the user terminal. The user terminal receives DL data from a predetermined subframe regardless of the subframe number of the received DCI.

The user terminal can decide allocation resources (subcarriers) of DL data based on the received DCI. Further, the user terminal can determine the timing of the last subframe (SF # n) of the subframe set based on information (e.g., information on the subframe set) notified by higher layer signaling and/or DCI.

The present embodiment can also be applied to a case where repetitive transmission (coverage enhancement) is used. Fig. 11B shows a case where 2 pieces of DCI (DCI #1 and #2) to which repeated transmission (repetition number 4) is applied are set in the same subframe set. Here, a case is assumed where downlink data is scheduled by DCI #1 and uplink data is scheduled by DCI # 2. That is, DCI #1 corresponds to DL allocation, and DCI #2 corresponds to UL grant.

Specifically, the user terminal starts reception of DL data (PDSCH) scheduled by DCI #1 from a predetermined subframe. The predetermined subframe may be a subframe (for example, SF # n + k) after a predetermined period from the last subframe (for example, SF # n) of the subframe set₁)。

As described above, in the second aspect, the reception start timing of DL data scheduled by DCI included in a subframe set is determined based on the last subframe constituting the subframe set, not the reception timing (reception subframe) of the DCI.

This can prevent the DCI (UL grant or DL assignment) included in the subframe set from colliding with the downlink data scheduled by the DL assignment. In addition, the reception timing is determined with reference to the last subframe of the subframe set (in particular, k is set)₁1), it is possible to suppress the generation of unused resources after the subframe set and efficiently utilize the resources. In addition, when a plurality of DL allocations are included in a subframe set, scheduling by each DL allocation can be performedThe allocation start positions of DL data are the same.

Note that, although fig. 11A and 11B show a case where a predetermined subframe to be the reception start timing of DL data is determined with reference to the last subframe of the subframe set, the present embodiment is not limited thereto. For example, the predetermined subframe may be determined based on a subframe in which the last DCI (downlink control channel) included in the subframe set is transmitted.

Fig. 12A and 12B show a case where the DL reception start timing is determined based on a subframe in which the last DCI (DCI #6/DCI #2) among the DCIs (DCIs #1 to #7/DCI #1 and #2) included in the subframe set is transmitted. Fig. 12A shows a case where the repetitive transmission is not used (normal coverage case), and fig. 12B shows a case where the repetitive transmission is applied (enhanced coverage case).

The radio base station can include information on a subframe (SF # m) in which the last DCI included in the subframe set is transmitted in DCI (for example, DCI #1 to #6 in fig. 12A) and notify the user terminal of the information. The user terminal determines a subframe (for example, SF # m) in which the last DCI is transmitted based on the information included in the DCI, and determines a subframe (for example, SF # m + k) after a predetermined period from the subframe₁) And starts UL transmission. Here, k can be set₁Is a value greater than 0 (e.g., 1).

In this way, by controlling the reception start timing of DL data scheduled by DCI included in a subframe set, it is possible to suppress the occurrence of collision between DCI included in the subframe set and DL data. In addition, when a plurality of DL allocations are included in a subframe set, the allocation start positions of DL data scheduled by the respective DL allocations can be the same. This can suppress the generation of unused resources and improve the utilization efficiency of resources.

Further, by determining the reception start timing of DL data based on the transmission timing of the last DCI included in the subframe set, the reception start timing of DL data (DL assignment) can be earlier than in fig. 11A and 11B. As a result, the resource utilization efficiency can be further improved, and the delay can be reduced.

The radio base station may notify the user terminal of information on a predetermined subframe which becomes a start timing of DL transmission, the information being included in the DCI. The information on the predetermined subframe may be any information for determining the predetermined subframe, and may be, for example, the number of the predetermined subframe itself or a subframe serving as a reference for determining the predetermined subframe. In this case, the radio base station can transmit information on a predetermined subframe to the user terminal, including the information on the predetermined subframe in each DCI transmitted in the same subframe set.

(Wireless communication System)

The following describes a configuration of a wireless communication system according to an embodiment of the present invention. In this wireless communication system, the wireless communication methods of the above-described respective embodiments are applied. The wireless communication methods of the above-described respective methods may be applied individually or in combination. Here, an NB-IoT terminal is exemplified as a user terminal whose usage band is limited to a narrowband domain, but is not limited thereto.

Fig. 13 is a schematic configuration diagram of a wireless communication system according to an embodiment of the present invention. The wireless communication system 1 shown in fig. 13 is an example in which an LTE system is employed in a network domain of a machine communication system. In the wireless communication system 1, Carrier Aggregation (CA) and/or Dual Connectivity (DC) can be applied in which a plurality of basic frequency blocks (component carriers) are integrated in a unit of a system bandwidth of the LTE system, which is 1. Note that, although both the downlink and the uplink of the LTE system are set to a system band from a minimum of 1.4MHz to a maximum of 20MHz, the present invention is not limited to this configuration.

The wireless communication system 1 may be referred to as SUPER 3G (SUPER 3G), LTE-a (LTE-Advanced), IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), or the like.

The radio communication system 1 includes a radio base station 10 and a plurality of user terminals 20A, 20B, and 20C wirelessly connected to the radio base station 10. The radio base station 10 is connected to the upper station apparatus 30, and is connected to the core network 40 via the upper station apparatus 30. The upper station apparatus 30 includes, for example, an access gateway apparatus, a Radio Network Controller (RNC), a Mobility Management Entity (MME), and the like, but is not limited thereto.

A plurality of user terminals 20(20A-20C) are able to communicate with the radio base station 10 in the cell 50. For example, the User terminal 20A is a User terminal supporting LTE (Rel-10 ago) or LTE-Advanced (also including Rel-10 afterward) (hereinafter, LTE terminal (LTE UE: LTE User Equipment (User Equipment))), and the other User terminals 20B, 20C are NB-IoT terminals (NB-IoT UEs (User Equipment))) that become communication devices in the machine communication system. Hereinafter, the user terminals 20A, 20B, and 20C are simply referred to as user terminals 20 unless they need to be distinguished in particular. The User terminal 20 may also be referred to as a UE (User Equipment) or the like.

The NB- IoT terminals 20B, 20C are user terminals using a band limited to a narrower band than the minimum system bandwidth supported by the existing LTE system. The NB- IoT terminals 20B and 20C may be terminals supporting various communication systems such as LTE and LTE-a, and may be not only fixed communication terminals such as electricity meters, gas meters, and vending machines, but also mobile communication terminals such as vehicles. The user terminal 20 may communicate with another user terminal 20 directly or via the radio base station 10.

In the wireless communication system 1, as radio Access schemes, Orthogonal Frequency Division Multiple Access (OFDMA) is applied to a downlink, and Single-Carrier Frequency Division Multiple Access (SC-FDMA) is applied to an uplink. OFDMA is a multicarrier transmission scheme in which a frequency band is divided into a plurality of narrow frequency bands (subcarriers) and data is mapped to each subcarrier to perform communication. SC-FDMA is a single carrier transmission scheme in which a system bandwidth is divided into bands each composed of one or consecutive resource blocks for each terminal, and a plurality of terminals use different bands to reduce interference between terminals. The uplink and downlink radio access schemes are not limited to these combinations.

In the radio communication system 1, as Downlink channels, a Downlink Shared Channel (Physical Downlink Shared Channel (PDSCH)) Shared by the user terminals 20, a Broadcast Channel (Physical Broadcast Channel (PBCH)), a Downlink L1/L2 control Channel, and the like are used. User data, higher layer control Information, and a predetermined SIB (System Information Block) are transmitted by the PDSCH. Also, MIB (Master Information Block) is transmitted through PBCH.

The Downlink L1/L2 Control channels include PDCCH (Physical Downlink Control Channel), EPDCCH (Enhanced Physical Downlink Control Channel), PCFICH (Physical Control Format Indicator Channel), PHICH (Physical Hybrid-ARQ Indicator Channel), and the like. Downlink Control Information (DCI) including scheduling Information of the PDSCH and the PUSCH and the like are transmitted through the PDCCH. The number of OFDM symbols for PDCCH is transmitted through PCFICH. Retransmission control information (HARQ-ACK) of the PUSCH is transmitted through the PHICH. EPDCCH and PDSCH are frequency division multiplexed, and used for transmitting DCI and the like in the same manner as PDCCH.

In the radio communication system 1, as Uplink channels, an Uplink Shared Channel (PUSCH), an Uplink L1/L2 Control Channel (PUCCH) and a Random Access Channel (PRACH) that are Shared by the user terminals 20 are used. The PUSCH may also be referred to as an uplink data channel. User data or higher layer control information is transmitted through the PUSCH. In addition, downlink radio Quality information (Channel Quality Indicator (CQI)), retransmission control information (HARQ-ACK), and the like are transmitted through the PUCCH. A random access preamble for establishing a connection with a cell is transmitted through the PRACH.

In addition, the MTC terminal/NB-IoT terminal-oriented channel may be represented by adding "M" representing MTC or "NB" representing NB-IoT, and the PDCCH/EPDCCH, PDSCH, PUCCH, PUSCH for the MTC terminal/NB-IoT terminal may also be referred to as M (NB) -PDCCH, M (NB) -PDSCH, M (NB) -PUCCH, M (NB) -PUSCH, etc., respectively. Hereinafter, unless otherwise specified, the term "PDCCH", PDSCH, PUCCH, PUSCH "will be simply referred to as" PDCCH ", PDSCH and PUSCH".

In the wireless communication system 1, as downlink Reference signals, Cell-specific Reference signals (CRS), Channel State Information Reference signals (CSI-RS), DeModulation Reference signals (DMRS), Positioning Reference Signals (PRS), and the like are transmitted. In addition, in the wireless communication system 1, as the uplink Reference Signal, a measurement Reference Signal (SRS: Sounding Reference Signal), a demodulation Reference Signal (DMRS), and the like are transmitted. In addition, the DMRS may also be referred to as a user terminal specific Reference Signal (UE-specific Reference Signal). The reference signal to be transmitted is not limited to this.

< radio base station >

Fig. 14 is a diagram showing an example of the overall configuration of a radio base station according to an embodiment of the present invention. The radio base station 10 includes at least a plurality of transmission/reception antennas 101, an amplifier unit 102, a transmission/reception unit 103, a baseband signal processing unit 104, a call processing unit 105, and a transmission line interface 106.

User data transmitted from the radio base station 10 to the user terminal 20 in the downlink is input from the upper station apparatus 30 to the baseband signal processing unit 104 via the transmission line interface 106.

The baseband signal processing section 104 performs transmission processing such as PDCP (Packet Data Convergence Protocol) layer processing, division/combination of user Data, RLC (Radio Link Control) layer transmission processing such as RLC retransmission Control, MAC (Medium Access Control) retransmission Control (for example, transmission processing of HARQ (Hybrid Automatic Repeat reQuest)), scheduling, transmission format selection, channel coding, Inverse Fast Fourier Transform (IFFT) processing, and precoding processing on user Data, and forwards the user Data to each transmitting/receiving section 103. Further, the downlink control signal is also subjected to transmission processing such as channel coding and inverse fast fourier transform, and is forwarded to each transmission/reception section 103.

Each transmitting/receiving section 103 converts the baseband signal, which is output after being precoded for each antenna from baseband signal processing section 104, into a radio frequency band and transmits the radio frequency band. The transmitting/receiving unit 103 can be configured by a transmitter/receiver, a transmitting/receiving circuit, or a transmitting/receiving device described based on common knowledge in the technical field of the present invention. The transmission/reception section 103 may be configured as an integrated transmission/reception section, or may be configured by a transmission section and a reception section.

The radio frequency signal frequency-converted in transmission/reception section 103 is amplified in amplifier section 102 and transmitted from transmission/reception antenna 101. The transmission and reception unit 103 can transmit and receive various signals in a narrow bandwidth (e.g., 180kHz) limited to a system bandwidth (e.g., 1 component carrier).

On the other hand, regarding the uplink signal, the radio frequency signal received by each transmission/reception antenna 101 is amplified by each amplifier unit 102. Each transmitting/receiving section 103 receives the uplink signal amplified by amplifier section 102. Transmission/reception section 103 frequency-converts the received signal into a baseband signal, and outputs the baseband signal to baseband signal processing section 104.

The baseband signal processing section 104 performs Fast Fourier Transform (FFT) processing, Inverse Discrete Fourier Transform (IDFT) processing, error correction decoding, reception processing of MAC retransmission control, and reception processing of the RLC layer and the PDCP layer on the user data included in the input uplink signal, and transfers the user data to the upper station apparatus 30 via the transmission path interface 106. The call processing unit 105 performs call processing such as setting or releasing a communication channel, status management of the radio base station 10, and management of radio resources.

The transmission line interface 106 transmits and receives signals to and from the upper station apparatus 30 via a predetermined interface. Further, the transmission path Interface 106 may transmit a reception signal (backhaul signaling) with the other Radio base station 10 via an inter-base station Interface (e.g., an optical fiber compliant with a Common Public Radio Interface (CPRI), an X2 Interface).

Transmission/reception section (transmission section) 103 transmits downlink control information in a subframe set for a downlink control channel in a predetermined bandwidth. A transmitting/receiving unit (receiving unit) 103 receives uplink data transmitted from the user terminal based on the downlink control information. Further, transmission/reception section (reception section) 103 can start reception of uplink data scheduled by downlink control information transmitted in the same subframe set from a predetermined subframe.

Fig. 15 is a diagram illustrating an example of a functional configuration of a radio base station according to an embodiment of the present invention. In addition, fig. 15 mainly shows functional blocks of characteristic parts in the present embodiment, and the radio base station 10 is provided with other functional blocks necessary for radio communication. As shown in fig. 15, the baseband signal processing unit 104 includes at least a control unit 301, a transmission signal generating unit (generating unit) 302, a mapping unit 303, a reception signal processing unit 304, and a measurement unit 305.

Control section 301 performs overall control of radio base station 10. The control unit 301 can be configured by a controller, a control circuit, or a control device described based on common knowledge in the technical field of the present invention.

The control unit 301 controls, for example, generation of a signal by the transmission signal generation unit 302 or allocation of a signal by the mapping unit 303. Further, the control unit 301 controls reception processing of the signal of the received signal processing unit 304 or measurement of the signal of the measurement unit 305. Further, control section 301 controls resource allocation (scheduling) of system information, PDSCH, and PUSCH. In addition, resource allocation to Synchronization signals (e.g., Primary Synchronization Signal (PSS)/SSS (Secondary Synchronization Signal)), NB-SS, or downlink reference signals such as CRS, CSI-RS, and DM-RS is controlled.

Further, control section 301 controls transmission signal generation section 302 and mapping section 303 so that various signals are assigned to the narrowband domain and transmitted to user terminal 20. Control section 301 controls such that, for example, downlink broadcast information (MIB, SIB (MTC-SIB)), PDCCH (also referred to as M-PDCCH, NB-PDCCH, etc.), PDSCH, etc. is transmitted in the narrowband domain. The narrow band domain (NB) is a narrower band domain (e.g., 180kHz) than the system band domain of the existing LTE system.

Furthermore, control section 301 receives PUSCH from the determined PUSCH resource in cooperation with transmission/reception section 103, received signal processing section 302, and measurement section 305. Furthermore, control section 301 transmits PDSCH using the determined PDSCH resources in cooperation with transmission signal generating section 302, mapping section 303, and transmission/reception section 103.

Transmission signal generating section (generating section) 302 generates a downlink signal (PDCCH, PDSCH, downlink reference signal, etc.) based on an instruction from control section 301 and outputs the downlink signal to mapping section 303. The transmission signal generation unit 302 can be configured by a signal generator, a signal generation circuit, or a signal generation device described based on common knowledge in the technical field of the present invention.

For example, based on an instruction from control section 301, transmission signal generation section 302 generates DCI (also referred to as DL assignment, UL grant, or the like) for assigning a PUSCH and/or a PDSCH to user terminal 20. In addition, the PDSCH is subjected to coding processing and modulation processing in accordance with a coding rate, a modulation scheme, and the like determined based on Channel State Information (CSI) and the like from each user terminal 20.

Mapping section 303 maps the downlink signal generated in transmission signal generating section 302 to a radio resource in a predetermined narrow band (for example, maximum 1 resource block) based on an instruction from control section 301, and outputs the result to transmitting/receiving section 103. The mapping unit 303 can be constituted by a mapper, a mapping circuit, or a mapping device explained based on common knowledge in the technical field of the present invention.

Received signal processing section 304 performs reception processing (for example, demapping, demodulation, decoding, and the like) on the received signal input from transmission/reception section 103. Here, the received signal is, for example, an uplink signal (PUCCH, PUSCH, uplink reference signal, etc.) transmitted from the user terminal 20. The received signal processing unit 304 can be constituted by a signal processor, a signal processing circuit, or a signal processing device described based on common knowledge in the technical field of the present invention.

Received signal processing section 304 outputs information decoded by the reception processing to control section 301. Further, the received signal processing unit 304 outputs the received signal or the signal after the reception processing to the measurement unit 305.

The measurement unit 305 performs measurements related to the received signal. The measurement unit 305 can be constituted by a measurement instrument, a measurement circuit, or a measurement device described based on common knowledge in the technical field of the present invention.

The measurement unit 305 may measure a Received Power (e.g., RSRP (Reference Signal Received Power)) of a Signal, a Received Quality (e.g., RSRQ (Reference Signal Received Quality)) or a channel state, etc. The measurement result may be output to the control unit 301.

< user terminal >

Fig. 16 is a diagram showing an example of the overall configuration of a user terminal according to an embodiment of the present invention. Note that, although detailed description is omitted here, a general LTE terminal may operate to operate as an NB-IoT terminal. The user terminal 20 includes at least a transmission/reception antenna 201, an amplifier unit 202, a transmission/reception unit 203, a baseband signal processing unit 204, and an application unit 205. The user terminal 20 may include a plurality of transmission/reception antennas 201, an amplifier unit 202, a transmission/reception unit 203, and the like.

The radio frequency signal received in the transmission-reception antenna 201 is amplified in the amplifier unit 202. Transmission/reception section 203 receives the downlink signal amplified by amplifier section 202.

Transmission/reception section 203 frequency-converts the received signal into a baseband signal, and outputs the baseband signal to baseband signal processing section 204. The transmitting/receiving unit 203 can be constituted by a transmitter/receiver, a transmitting/receiving circuit, or a transmitting/receiving device described based on common knowledge in the technical field of the present invention. The transmission/reception section 203 may be configured as an integrated transmission/reception section, or may be configured by a transmission section and a reception section.

The baseband signal processing section 204 performs FFT processing, error correction decoding, retransmission control reception processing, and the like on the input baseband signal. The downlink user data is forwarded to the application unit 205. The application unit 205 performs processing and the like relating to a layer higher than the physical layer or the MAC layer. In addition, in the downlink data, the broadcast information is also forwarded to the application unit 205.

On the other hand, uplink user data is input from the application unit 205 to the baseband signal processing unit 204. Baseband signal processing section 204 performs transmission processing of retransmission control information (HARQ-ACK), channel coding, precoding, Discrete Fourier Transform (DFT) processing, IFFT processing, and the like, and forwards the result to transmitting/receiving section 203.

Transmission/reception section 203 converts the baseband signal output from baseband signal processing section 204 into a radio frequency band and transmits the radio frequency band. The radio frequency signal frequency-converted by the transmission/reception section 203 is amplified by the amplifier section 202 and transmitted from the transmission/reception antenna 201.

A transmission/reception section (reception section) 203 receives downlink control information included in a subframe set for a downlink control channel in a predetermined bandwidth. Further, the transmission/reception unit (reception unit) 203 can receive downlink control information including information on the last subframe to which the downlink control channel is allocated in the subframe set. Further, the transmission and reception unit (reception unit) 203 can receive information on the subframe set.

Fig. 17 is a diagram showing an example of a functional configuration of a user terminal according to an embodiment of the present invention. In addition, fig. 17 mainly shows functional blocks of characteristic parts in the present embodiment, and the user terminal 20 is provided with other functional blocks necessary for wireless communication. As shown in fig. 17, the baseband signal processing unit 204 included in the user terminal 20 includes at least a control unit 401, a transmission signal generation unit (generation unit) 402, a mapping unit 403, a reception signal processing unit 404, and a measurement unit 405.

The control unit 401 performs overall control of the user terminal 20. The control unit 401 can be configured by a controller, a control circuit, or a control device described based on common knowledge in the technical field of the present invention.

Control section 401 controls generation of a signal by transmission signal generation section 402 or allocation of a signal by mapping section 403, for example. Further, the control unit 401 controls reception processing of the signal of the received signal processing unit 404 or measurement of the signal of the measurement unit 405.

Control section 401 acquires downlink signals (PDCCH, PDSCH, downlink reference signals) transmitted from radio base station 10 from received signal processing section 404. Based on the downlink signal, control section 401 controls generation of Uplink Control Information (UCI) such as retransmission control information (HARQ-ACK) and Channel State Information (CSI) or uplink data.

Further, control section 401 controls uplink data transmission based on the downlink control information. For example, control section 401 can control such that uplink data transmission scheduled by downlink control information included in the same subframe set is started from a predetermined subframe. Specifically, control section 401 can start uplink data transmission scheduled by downlink control information included in the same subframe set from a subframe after a predetermined period from the last subframe in the subframe set (see fig. 7 and 8).

Further, control section 401 can start uplink data transmission scheduled by downlink control information included in the same subframe set, from a subframe after a predetermined period from the last subframe to which a downlink control channel is allocated in the subframe set (see fig. 9 and 10).

Further, control section 401 can repeat transmission of uplink data scheduled by downlink control information included in the same subframe set from a predetermined subframe. Further, control section 401 can control such that uplink data transmissions scheduled by downlink control information included in the same subframe set are transmitted using a single carrier, respectively. In addition, uplink data scheduled by downlink control information included in a subframe set may be allocated to different subcarriers within the same PRB.

Further, control section 401 can control such that downlink data reception scheduled by the downlink control information included in the subframe set is started from a predetermined subframe (see fig. 11A and 11B, and fig. 12A and 12B).

Further, control section 401 transmits PUSCH from PUSCH resources in cooperation with transmission signal generation section 402, mapping section 403, and transmission/reception section 203. Furthermore, control section 401 receives PDSCH from PDSCH resources in cooperation with transmission/reception section 203, received signal processing section 404, and measurement section 405.

Transmission signal generating section 402 generates an uplink signal (PUCCH, PUSCH, uplink reference signal, and the like) based on an instruction from control section 401, and outputs the uplink signal to mapping section 403. The transmission signal generation unit 402 can be configured by a signal generator, a signal generation circuit, or a signal generation device described based on common knowledge in the technical field of the present invention.

Transmission signal generation section 402 generates Uplink Control Information (UCI) and/or uplink data, for example, based on an instruction from control section 401. Further, transmission signal generation section 402 generates a PUSCH for transmitting UCI and/or uplink data based on an instruction from control section 401. For example, when receiving DCI for allocating PUSCH to user terminal 20, transmission signal generation section 402 is instructed from control section 401 to generate PUSCH. Further, transmission signal generation section 402 generates a PUCCH to transmit UCI based on an instruction from control section 401.

Mapping section 403 maps the uplink signal generated in transmission signal generating section 402 to a resource (for example, PUSCH resource or PUCCH resource) based on an instruction from control section 401, and outputs the uplink signal to transmitting/receiving section 203. The mapping unit 403 can be constituted by a mapper, a mapping circuit, or a mapping device explained based on common knowledge in the technical field of the present invention.

Received signal processing section 404 performs reception processing (for example, demapping, demodulation, decoding, and the like) on the received signal input from transmission/reception section 203. Here, the reception signal is, for example, a downlink signal (downlink control signal, downlink data signal, downlink reference signal, etc.) transmitted from the radio base station 10. The received signal processing unit 404 can be constituted by a signal processor, a signal processing circuit, or a signal processing device described based on common knowledge in the technical field of the present invention.

The received signal processing unit 404 outputs information decoded by the reception processing to the control unit 401. Received signal processing section 404 outputs, for example, broadcast information, system information, RCC signaling, DCI, and the like to control section 401. Further, the received signal processing unit 404 outputs the received signal or the signal after the reception processing to the measurement unit 405.

The measurement unit 405 performs measurements related to the received signal. The measurement unit 405 can be configured by a measurement instrument, a measurement circuit, or a measurement device described based on common knowledge in the technical field of the present invention.

The measurement unit 405 may, for example, measure the received power (e.g., RSRP), the received quality (e.g., RSRQ), or the channel state of the received signal. The measurement result may be output to the control unit 401.

< hardware Structure >

The block diagrams used in the description of the above embodiments represent blocks in functional units. These functional blocks (structural units) are implemented by any combination of hardware and/or software. Note that the means for implementing each functional block is not particularly limited. That is, each functional block may be realized by 1 device that is physically combined, or may be realized by a plurality of devices that are connected by wire or wirelessly by 2 or more devices that are physically separated.

For example, the radio base station, the user terminal, and the like according to the embodiment of the present invention can function as a computer that performs the processing of the radio communication method of the present invention. Fig. 18 is a diagram showing an example of hardware configurations of a radio base station and a user terminal according to an embodiment of the present invention. The radio base station 10 and the user terminal 20 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

In the following description, the term "device" may be replaced with circuits, devices, units, and the like. The hardware configuration of the radio base station 10 and the user terminal 20 may include one or more of each illustrated device, or may not include some of the devices.

Each function in the radio base station 10 and the user terminal 20 is realized by reading predetermined software (program) into hardware such as the processor 1001 and the memory 1002, performing an operation by the processor 1001, and controlling communication by the communication device 1004 and reading and/or writing of data in the memory 1002 and the storage 1003.

The processor 1001 controls the entire computer by operating an operating system, for example. The processor 1001 may be constituted by a Central Processing Unit (CPU) including an interface with peripheral devices, a control device, an arithmetic device, a register, and the like. For example, the baseband signal processing unit 104(204), the call processing unit 105, and the like may be implemented in the processor 1001.

Further, the processor 1001 reads a program (program code), a software module, or data from the storage 1003 and/or the communication device 1004 to the memory 1002, and executes various processes based on them. As the program, a program that causes a computer to execute at least a part of the operations described in the above embodiments is used. For example, the control unit 401 of the user terminal 20 may be realized by a control program stored in the memory 1002 and operated in the processor 1001, and may be similarly realized with respect to other functional blocks.

The Memory 1002 is a computer-readable recording medium, and may be configured with at least one of a ROM (Read Only Memory), an EPROM (erasable Programmable ROM), a RAM (Random Access Memory), and the like. The memory 1002 may also be referred to as a register, cache, main memory (primary storage), or the like. The memory 1002 can store an executable program (program code), a software module, and the like for implementing the wireless communication method according to the embodiment of the present invention.

The storage 1003 is a computer-readable recording medium, and may be constituted by at least one of an optical disk such as a CD-ROM (compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk, and a flash memory. The storage 1003 may also be referred to as a secondary storage device.

The communication device 1004 is hardware (transmission/reception device) for performing communication between computers via a wired and/or wireless network, and is also referred to as a network device, a network controller, a network card, a communication module, or the like, for example. For example, the transmission/ reception antennas 101 and 201, the amplifier units 102 and 202, the transmission/ reception units 103 and 203, the transmission line interface 106, and the like described above may be implemented in the communication device 1004.

The input device 1005 is an input device (for example, a keyboard, a mouse, or the like) that receives an input from the outside. The output device 1006 is an output device (for example, a display, a speaker, or the like) that performs output to the outside. The input device 1005 and the output device 1006 may be integrated (for example, a touch panel).

Each device such as the processor 1001 and the memory 1002 is connected to a bus 1007 for information communication. The bus 1007 may be constituted by one bus or may be constituted by buses different among devices.

The radio base station 10 and the user terminal 20 may be configured by hardware such as a microprocessor, a Digital Signal Processor (DSP), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), and an FPGA (Field Programmable Gate Array), and a part or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be installed by at least one of these hardware.

In addition, terms described in the present specification and/or terms necessary for understanding the present specification may be replaced with terms having the same or similar meanings. For example, the channels and/or symbols may also be signals (signaling). Further, the signal may also be a message. Further, a Component Carrier (CC) may also be referred to as a cell, a frequency Carrier, a Carrier frequency, and the like.

The radio frame may be configured of one or more periods (frames) in the time domain. The one or more periods (frames) constituting the radio frame may also be referred to as subframes. Further, a subframe may also be composed of one or more slots in the time domain. Further, the slot may also be composed of one or more symbols (OFDM symbol, SC-FDMA symbol, etc.) in the time domain.

The radio frame, subframe, slot, and symbol all represent a unit of time when a signal is transmitted. The radio frame, subframe, slot, and symbol may be referred to by other names corresponding to each. For example, 1 subframe may be referred to as a Transmission Time Interval (TTI), a plurality of consecutive subframes may be referred to as TTIs, and 1 slot may be referred to as a TTI. That is, the subframe or TTI may be a subframe (1ms) in the conventional LTE, may be a period shorter than 1ms (for example, 1 to 13 symbols), or may be a period longer than 1 ms.

Here, the TTI refers to, for example, the minimum time unit of scheduling in wireless communication. For example, in the LTE system, the radio base station performs scheduling for allocating radio resources (such as a frequency bandwidth and transmission power usable by each user terminal) to each user terminal in units of TTIs. In addition, the definition of TTI is not limited thereto.

A TTI having a duration of 1ms may also be referred to as a normal TTI (TTI in LTE rel.8-12), a normal (normal) TTI, a long (long) TTI, a normal subframe, a normal (normal) subframe, or a long (long) subframe, etc. A TTI shorter than a normal TTI may be referred to as a shortened TTI, a short TTI, a shortened subframe, a short subframe, or the like.

A Resource Block (RB) is a Resource allocation unit in the time domain and the frequency domain, and may include one or a plurality of continuous subcarriers (subcarriers) in the frequency domain. In addition, an RB may include one or more symbols in the time domain, and may have a length of 1 slot, 1 subframe, or 1 TTI. The 1TTI and 1 subframe may be formed of one or more resource blocks. In addition, an RB may also be referred to as a Physical Resource Block (PRB), a PRB pair, an RB peer, or the like.

In addition, a Resource block may also be composed of one or more Resource Elements (REs). For example, 1RE may be a radio resource region of 1 subcarrier and 1 symbol.

The structures of the radio frame, the subframe, the slot, the symbol, and the like are merely examples. For example, the number of subframes included in the radio frame, the number of slots included in the subframe, the number of symbols and RBs included in the slot, the number of subcarriers included in the RB, the number of symbols in the TTI, the symbol length, the Cyclic Prefix (CP) length, and other configurations can be variously changed.

The information, parameters, and the like described in the present specification may be expressed by absolute values, relative values to predetermined values, or other corresponding information. For example, the radio resource may be indicated by a predetermined index.

Information, signals, and the like described in this specification can be represented using any of a variety of different technologies. For example, data, commands, instructions, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or photons, or any combination thereof.

Further, software, commands, information, and the like may be transmitted or received via a transmission medium. For example, where the software is transmitted from a website, server, or other remote source using a wired technology (coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), etc.) and/or a wireless technology (infrared, microwave, etc.), such wired and/or wireless technologies are included in the definition of transmission medium.

In addition, the radio base station in this specification may be replaced with a user terminal. For example, the aspects and embodiments of the present invention may be applied to a configuration in which communication between a radio base station and a user terminal is replaced with communication between a plurality of user terminals (Device-to-Device (D2D)). In this case, the user terminal 20 may be configured to have the functions of the radio base station 10. The terms "upstream" and "downstream" may be replaced with "side". For example, the uplink channel may be replaced with a side channel.

Similarly, the user terminal in this specification may be replaced with a radio base station. In this case, the radio base station 10 may be configured to have the functions of the user terminal 20.

The embodiments and modes described in this specification may be used alone, may be used in combination, or may be switched depending on execution. Note that the notification of the predetermined information (for example, the notification of "X") is not limited to be explicitly performed, and may be performed implicitly (for example, by not performing the notification of the predetermined information).

The information notification is not limited to the embodiments and modes described in the present specification, and may be performed by other methods. For example, the Information may be notified by physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), higher layer signaling (e.g., RRC (Radio Resource Control) signaling), broadcast Information (MIB (Master Information Block)), SIB (System Information Block), etc.), MAC (Medium Access Control) signaling, other signals, or a combination thereof. The RRC signaling may be referred to as an RRC message, and may be, for example, an RRC connection setup (RRCConnectionSetup) message, an RRC connection reconfiguration (RRCConnectionReconfiguration) message, or the like. In addition, the MAC signaling may be notified by a MAC Control Element (MAC CE (Control Element)), for example.

The aspects/embodiments described in the present specification can be applied to LTE (Long Term Evolution), LTE-a (LTE-Advanced), LTE-B (LTE-Beyond), super 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), new-RAT (Radio Access Technology), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11(Wi-Fi (registered trademark)), IEEE 802.16(WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), and systems using other appropriate wireless communication methods and/or next-generation systems expanded based thereon.

The processing procedures, sequences, flowcharts, and the like of the respective modes/embodiments described in the present specification may be changed in order as long as they are not contradictory. For example, elements of the various steps are presented in the order of illustration in the method described in the present specification, and the method is not limited to the specific order presented.

The present invention has been described in detail above, but it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in the present specification. For example, the above embodiments may be used alone or in combination. The present invention can be implemented as modifications and variations without departing from the spirit and scope of the present invention defined by the claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

The present application is based on the application 2016-. The contents of which are all incorporated herein.

Claims (7)

1. A user terminal, comprising:

a reception unit configured to receive downlink control information in a predetermined bandwidth on a downlink control channel included in a predetermined period; and

a control unit that controls uplink data transmission based on the downlink control information,

the control unit determines a subframe in which the downlink control channel is transmitted last in the predetermined period based on the number of repetitions notified by the downlink control information, and controls a start timing of uplink data transmission with reference to the subframe in which the downlink control channel is transmitted last in the predetermined period.

2. The user terminal of claim 1,

the downlink control information transmitted in the predetermined period includes information on a subframe in which the downlink control channel is transmitted last in the predetermined period.

3. The user terminal of claim 1 or claim 2,

the downlink control information is repeatedly transmitted via different subframes.

4. A user terminal, comprising:

a reception unit configured to receive downlink control information in a predetermined bandwidth on a downlink control channel included in a predetermined period; and

a control unit which controls downlink data reception based on the downlink control information,

the control unit determines a subframe in which the downlink control channel is transmitted last in the predetermined period based on the number of repetitions notified by the downlink control information, and controls a start timing of downlink data reception with reference to the subframe in which the downlink control channel is transmitted last in the predetermined period.

5. A wireless base station, comprising:

a transmission unit configured to transmit downlink control information in a predetermined bandwidth by using a downlink control channel included in a predetermined period; and

a receiving unit configured to receive uplink data transmitted by the user terminal based on the downlink control information,

the transmission unit notifies, using the downlink control information, a repetition number by which a subframe to which a downlink control channel is transmitted last in the predetermined period can be determined,

the receiving unit controls a start timing of uplink data reception with reference to a subframe in which the downlink control channel is transmitted last in the predetermined period.

6. A wireless communication method for a user terminal, the wireless communication method comprising:

receiving downlink control information on a downlink control channel included in a predetermined period in a predetermined bandwidth; and

a step of transmitting uplink data based on the downlink control information,

and determining a subframe in which the downlink control channel is transmitted last in the predetermined period based on the number of repetitions notified by the downlink control information, and controlling a start timing of uplink data transmission with reference to the subframe in which the downlink control channel is transmitted last in the predetermined period.

7. A communication system having a user terminal and a base station, characterized in that,

the user terminal has:

a reception unit configured to receive downlink control information in a predetermined bandwidth on a downlink control channel included in a predetermined period; and

a control unit that controls uplink data transmission based on the downlink control information,

the control unit determines a subframe in which the downlink control channel is transmitted last in the predetermined period based on the number of repetitions notified by the downlink control information, and controls the start timing of the uplink data transmission with reference to the subframe in which the downlink control channel is transmitted last in the predetermined period,

the base station includes:

a transmitting unit configured to transmit the downlink control information; and

and a receiving unit configured to receive uplink data transmitted by the user terminal based on the downlink control information.

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